The present invention relates to keyboard lighting and more particularly, to incorporating a lighting device into the keyboard of a portable computer.
Either back or front lighting can be used to illuminate a full travel keyboard in a dimly lit ambient environment. Back lighting requires that an incandescent light bulb or a light-emitting diode (LED) light source be placed inside the keyboard. When power is applied, the light source illuminates by transmission from the rear the legends on the key caps of the keyboard. Front lighting requires that a light source, typically with an adjustable brightness incandescent light bulb, be place above the keyboard. When power is applied, light from the lamp illuminates by reflection off the legends on the key caps.
Each keyboard-lighting technique has advantages and disadvantages. Back lighting has the advantage in that it is integrated with the keyboard to eliminate annoying vision obstructions onto and behind the keyboard. In back lighting, each key is illuminated to avoid finger shadows on the key caps and provide good key cap legend readability. Also, the brightness of the keyboard can be easily adjusted to avoid display reflections and suit different lighting conditions and user preferences.
However, back lighting has disadvantages in that the keyboard itself is usually thicker to accommodate light source and other support electronics. Back lit keyboards are also quite expensive due to low volume and unusual, customized electronics. They suffer from low reliability due to electronic complexity and require a relatively large amount of power.
Front lighting has an advantage in that it is much lower in cost to implement. However, prior art front lighting also has disadvantages. Among them being that the lamp usually obstructs the user""s view of the computer screen and possibly access to keys on the keyboard because the lamp is usually positioned above the keyboard in the user""s line of sight.
For the above reasons and other reasons, prior art back lighting or front lighting techniques have provided optimal keyboard lighting technique.
Therefore, it is an object of the present invention to provide a new electroluminescent keyboard light.
It is another object of the present invention to provide a keyboard level light source.
Further objects of the invention is to provide a light source for a computer keyboard that is inexpensive, efficient and easy to operate.
In accordance with the present invention, a lighting source, such as a light emitting diode (LED), is incorporated into the shaft of a pointing device positioned among the keys of a keyboard. A light shield or cap is attached to the top of the pointing device so that the light from the light source extends outwardly and horizontally across the keyboard to provide light to the keyboard without interfering with the viewing of the computer screen. Reflecting surfaces can be incorporated into the underside of the cap and at the base of the light source to intensify the light provided to the keyboard. The light is activated when the pointing device is raised to its normal operating position. When ambient lighting is sufficient, the lighting function may be disables when the pointed is raised.